Blue Light Initiated Photopolymerization: Kinetics and Synthesis of Superabsorbent and Robust Poly(N,N′-dimethylacrylamide/Sodium Acrylate) Hydrogels

Abstract

The kinetics of blue light and camphorquinone (CQ)/diphenyl iodonium hexafluorophosphate (DPI) initiated photopolymerization of N,N′-dimethylacrylamide (DMMA)/sodium acrylate (SA) was studied using real-time photo differential scanning calorimetry (photo-DSC) and photorheological analysis. The CQ/DPI combined photoinitiation led to a high polymerization rate and double bond conversion degree. The maximum polymerization rate (Rpmax) was found to be proportional to the square root of light intensity and CQ concentration (<1.0 wt %) and the gelation kinetics was linearly proportional to light intensity and CQ concentration. Poly(DMAA/SA) hydrogels synthesized via such blue light initiated photopolymerization exhibited superior water absorbability (∼750 g/g), robust mechanical properties (∼2500% strain and ∼0.6 MPa stress), and good dimensional stability.